Profile milling machines



P 1961 A. D. GUNDERSON 3,000,270

PROFILE MILLING MACHINES Filed March 18, 1955 7 Sheets-Sheet 1 INVENTOR 2 pgwsm m +11 ATTORNEYS PROFILE MILLING MACHINES INVENTOR ATTORNEYS 7 Sheets-Sheet 3 Filed March 18, 1955 lI-i Se t. 19, 1961 A. D. GUNDERSON PROFILE MILLING MACHINES 7 Sheets-Sheet 4 Filed March 18, 1955 K Mm v. INVENT 0'.

BY "(1&1 Jinx ATTORNEYJ.

Sept. 19, 1961 A. D. GUNDERSON PROFILE MILLING MACHINES 7 Sheets-Sheet 5 Filed March 18, 1955 JINVENTOR;

4mm? Tick Tick ATTORNEYQ Sept. 19, 1961 A. D. GUNDERSON 3,000,270

PROFILE MILLING MACHINES I Filed March 18, 1955 7 Sheets-Sheet 6 1N VENTOR M BY I Sept. 19, 1961 A. D. GUNDERSON 3,000,270

PROFILE MILLING MACHINES Filed March 18, 1955 7 Sheets-Sheet 7 ATTORNEYS United States Patent 3,000,270 PROFILE MILLING MACHINES Allen D. Gunderson, Racine, Wis., assignor to George Gorton Machine Co., Racine Wis., a corporation of Wisconsin Filed Mar. 18, 1955, 'Ser. No. 495,245 12 Claims. (Cl. 90-131) This invention relates to profile milling machines, and particularly to such machines of the powered master, pantographic types in which a pantograph mechanism is actuated by a powered master to move a milling cutter over a work piece in scaled reproduction of the movements of the master; and the nature and objects of the invention will be readily recognized and understood by those skilled in the arts involved from the following explanation and detailed description of the accompanying drawings illustrating one possible embodiment or mechanical expression of my invention and the various features thereof in what I at present believe to be a preferred form, from among various other forms, embodiments, expressions and combinations of which the invention is capable within the broad spirit and scope thereof as defined by the claims hereto appended.

It is a general object of the invention to improve the productivity, the quality of work, and the efficiency generally of profile milling machines of the powered master, pantographic types, while reducing the time and attention, the skill and the manual operations required from an operator of such a machine.

Another object is to provide such a profile milling machine capable of efficiently automatically profile milling undercut internal or external contours in a work piece.

A further object is to provide such a machine in which the milling cutter is moved automatically upon completion of a profile milling cycle of the machine to a position clear of the completed profile milled surfaces on the work piece for free and unobstructed retraction of the cutter from and feed thereof to a down position relative to a work piece.

Another object is to provide such a machine in which the tracer stylus of the powered master unit of the machine is moved automatically at the completion of a milling cycle to a position spaced from the master profile surface and simultaneously eifects movement of the milling cutter in the work piece to a position clear of the completed profile surface milled thereby and of the work piece for free, unobstructed retraction or withdrawal of the milling cutter from and feed thereof to such position.

A further object is to provide for the automatic return upon the start of a milling cycle of the tracer stylus and the milling cutter to tracing relation with the master profile and to profile milling relation in the work piece, respectively, from the positions into which the tracing stylus and milling cutter are moved and held for milling cutter retraction at the end of the preceding milling cycle.

A further object is to provide a profile milling machine of the powered master, tracer controlled pantographic type having an automatic profile milling cycle with automatic feed of a milling cutting into a work piece at the start of the milling cycle and automatic retraction or withdrawal of the milling cutter from the work piece at the completion of the milling cycle.

3,090,270 Patented Sept. 19, 1961 "ice Another primary object of the invention is to provide a powered master unit for dictating and controlling the movements of a milling cutter in a work piece for performing under-cut profile milling, in which the tracer stylus of the master unit is moved automatically to a position spaced from the master profile of the unit after the tracer stylus has completed a cycle around the master profile and is returned automatically to tracing relation with the master profile following the start of the tracer stylus on its next cycle around the master profile.

A further object is to provide a powered master unit with an endless master profile and tracer stylus movable around said profile by power drive thereof in one direction through a tracing cycle in which the tracer stylus upon reversal of its direction of movement is automatically switched or guided from the master profile to and held in an inactive position spaced from the master profile and is automatically guided back to tracing engagement by movement of the tracer stylus in the direction of movement of the power driven tracing cycle thereof.

With the foregoing and various other objects, features and results in view which will be recognized from the following detailed description and explanation, my invention consists in certain novel designs, constructions and arrangements of parts and components and in combinations and sub-combinations thereof, as well as in various sequences of operations performed thereby, all as will be more fully and particularly referred to and specified hereinafter.

Referring to the accompanying drawings in which similar reference characters refer to corresponding parts and elements throughout the figures thereof:

FIG. 1 is a view in front elevation of a machine embodying the several features of the invention with the cutter spindle thereof in its retracted position raised from the work piece on the worktable.

FIG. 2 is a top plan view of the machine of FIG. 1, with the tracer stylus and cutter spindle at the start of the tracing and milling cycles thereof.

FIG. 3 is a top plan view of the powered master unit of the machine of FIG. 1, showing the tracer stylus starting its tracing cycle around the master profile surface of the unit.

FIG. 4 is a detail view partly in front elevation and partly in vertical section, of the forming guide and cutter spindle downfeed mechanism, the solenoid controlled valve unit for the pressure fluid actuated cylinder and piston unit of the mechanism being schematically shown.

FIG. 5 is a view in top plan of the vertically movable forming guide and its mounting and supporting structure, with portions of the head of the machine on which said structure is mounted being also shown in top plan.

FIG. 6 is a vertical section taken as on the line 6-6 of FIG. 3, and showing particularly the rotatable tracer stylus holder and portions of the powered drive there for.

FIG. 7 is a detail view in vertical section taken as on the line 7--7 of FIG. 3, showing the hub of the gate member and its mounting on the master.

FIG. 8 is a schematic wiring diagram of the power and control circuits for the machine of FIG. 1.

FIG. 9 is a view, more or less diagrammatic, in vertical section through a work piece showing a milling cutter posie 3 tioned by the machine of FIG. 1 in position milling an undercut profiled surface on the work piece, the milling cutter being shown in elevation.

FIG. is a top plan view, more or less diagrammatic, showing the milling cutter in position displaced from the work piece and the tracer stylus moved from the master profile surface to its inactive position.

FIG. 11 is a fragmentary view in top plan of the master unit showing the tracer stylus moved from tracing position to its inactive position and also showing the tracer stylus engaged by the retractor unit and in position on the gate member being guided thereby to inactive position.

The profile milling machine which'I have selected and illustrated and described herein as an example embodiment of an organization of my invention and of the several features thereof, and as example embodiments of the several components of the invention which are combined to form such example machine, happens to be of the vertical column type having but one cutter spindle unit actuated by a single pantograph unit driven from a single powered master unit. However, machines embodying the invention are not limited to the signal cutter spindle, pantograph and powered master type of the present example or to the particular vertical supporting column arrangement here shown, as it is contemplated and intended that the invention may be embodied in a multiple spindle machine either made up of a plurality of single spindle machine organizations, such as presented by the example machine, or as a multiple spindle organization having a single and unitary supporting structure with multiple pantograph and powered master units. And further, while the selected example is shown as a machine for material removing by milling by the use of milling cutters, it is not thereby intended to limit the invention to machines for performing material removal by so-called milling operations as any other suitable operations for material removal adapted to form on a work piece the desired profile surfaces may be used, such, for example, as grinding operations utilizing suitable grinding tools. Hence, the terms milling or milling cutter are used herein and in the appended claims in a broad and generic sense to mean and include grinding and other operations for material removal and the tools used to perform such operations.

The machine and the powered master unit of the invention, as expressed in this example, are primarily intended for undercut forms of profile milling with automatic milling cycles, but as will be more fully developed herein after, a powered master unit and an organization of which it may form a component, are adapted to and capable of efliicient operation to profile mill automatically contours of non-undercut forms having straight wall surfaces in planes parallel with or at an angle to the axis of the milling cutter. Hence, a powered master unit, as well as a machine in which incorporated, embodying my present invention, is of general use for profile milling automatically form a master profile.

General organization The machine of the example hereof in its general organization includes a supporting base structure B on which there is mounted a generally vertically disposed supporting column structure C with a worktable T mounted and positioned adjacent the column structure at one side thereof, portions only of the supporting base structure B and the worktable T being shown in the drawings. In this instance the worktable T is mounted and located in horizontally disposed position and is of the indexing type operated and controlled by a suitable indexing mechanism (not shown) which includes a driving or indexing motor IM and controlling and interlock circuits therefor which are shown schematically in FIG. 8 of the drawings, and which will be hereinafter described and explained. However, a machine of my invention or a powered m'asterunit or a downfeed mechanism thereof, is .not limited to use. ofor .4 with a worktable of the indexing type as any form or type of worktable may be utilized, including worktables of the non-indexing or stationary forms.

A cutter spindle unit assembly 20 is mounted and supported from the column structure C by a system of pivotally connected, horizontally swingable links 14 and 15. Thus mounted and supported, the cutter spindle unit 20 is universally laterally movable over a work piece that has been moved to working position therebeneath by the indexing worktable T. The cutter spindle unit 24} is mounted for and constrained, to straight-line vertical movements upwardly and downwardly on and relative to its supporting linkage system. A vertically disposed cutter spindle 21 is journaled in the unit 20 and is movable bodily vertically axially therewith toward and from a work piece positioned thereberieath. The cutter spindle 21 of the unit 20 is power driven by a motor SM that is swingably supported from the column structure C and is in driving connection with the cutter spindle by a belt 22. Motor SM may, as in this'example, be horizontally swingably supported from the column'structure C by the arm 23 pivotally connected to the column structure C with a push-pull rod 24 pivotally connectedrconcentric with the axis of the motor and at the opposite end pivotally coupled to the cutter spindle unit 20 concentric with the axis of the cutter spindle 21. The motor SM includes the driving pulley v25 and the cutter spindle 21 has the driven pulley 26 thereon adjacent the lower end thereof with the belt 22 mounted on and connecting the driving pulley 25 and driven pulley 26 for rotating the cutter spindle. The push-pull rod 24 maintains at all times the proper spacing between the driving pulley 25 of the motor and the driven pulley 26 of the cutter spindle.

A powered master unit M embodying my present invention is mounted in horizontally disposed position on the supporting column structure C spaced thereon rearwardly or outwardly from the system of links 14 and 15 and the cutter spindle unit 20 mounted on such links. This powered master unit M includes a tracer stylus assembly S which is power driven for tracing engagement with and around a master profile surface provided by the master unit, from a motor MM mounted and supported as a component of the master unit. In accordance with a major feature of the invention provision is made for automatically displacing the tracer stylus assembly S to a position spaced from the master profile surface of the master unit upon completion of a cycle of movement of the tracer stylus and for automatically returning the tracer stylus from such position to tracing engagement with the master profile surface at the start of the next cycle of the tracer stylus assembly.

A pantograph linkage identified generally by thereference character P is mounted and pivotally supported on and from the column structure C. This pantograph linkage is suitablably coupled with the cutter spindle unit mounting link 15 for universally laterally moving the cutter spindle unit 20 and its cutter spindle 21 mounted thereon over a work piece on the table T. 'The pant0- graph linkage P includes. a tracer arm 34 which is suitably coupled with the power driven tracer stylus assembly S of the powered master unit M so that the pantograph linkage is actuated thereby to transmit movements of the tracer stylus assembly S to the cutter spindle assembly 29 and its cutter spindle 21 as movements in precise scaled reproduction of the movements of the tracer stylus assembly as controlled and dictated by the master profile surface of the master unit.

The machine of the invention of this particular example also includes as components thereof a forming guide asembly G which is mounted for vertical movements bodily upwardly and downwardly in operative engagement with the cutter spindle unit 20 at the upper side thereof for vertically bodily moving that unit to thereby feed the cutter spindle 21 thereof downwardly to and to withdraw the cutter spindle upwardlyrfrom a down position relative to the table T and a work piece thereon. A powered feed mechanism of the invention, identified generally by the reference character F, is operatively coupled with the movably mounted forming guide G for automatically effecting powered downfeed and withdrawal of the cutter spindle assembly 20 and its cutter spindle 21 to and from a work piece on the table T in a manner to be hereinafter described and explained.

The organization formed by the combination of components and controls therefor of the specific example machine hereof is semi-automatic in operation in that each profile miling cycle is initiated manually by the operator through a manual control. However, once the profile miling cycle is started, the machine operates fully automatically through the cycle and is automatically stopped upon the completion of the cycle. The movement of the tracer stylus assembly S into tracing engagement with the master profile and the movement effected thereby of the cutter spindle S into working engagement with the work piece are carried out automatically following the manual initiation of the milling cycle. Similarly, upon completion of the milling cycle the tracer stylus S and the cutter spindle 21 are moved automatical- 1y to inactive positions withdrawn from and clear of-the master profile of the master unit and the profile milled contours on the work piece, respectively. In the complete automatic cycle of the example machine, the cutter spindle feed mechanism F is also operated to automatically feed thec utter spindle to its down position relative 'to the work piece at the start of the milling cycle and to withdraw the cutter spindle from its down position upon the completion of the cycle after the cutter spindle has been moved away from the profile milled surfaces in the work piece automatically by the corresponding movement of the tracer stylus assembly S from tracing engagement with the master profile surface of the master unit.

Pantograph assembly and mounting In this specific example the vertical column structure C includes at the upper end thereof a forwardly and horizontally extending neck N. From one side of the neck N an arm extends and is provided at its outer .end with the vertically spaced ears 11 and 12 in and between which one end of the link 14 of the cutter spin- =dle unit carrying linkage is pivotally mounted. The other link 15 of this linkage is pivotally connected to the outer end of the link 14. The link 15 at its outer end is provided with the vertically spaced arms 16 and 17 with the cutter spindle unit assembly 20 being mounted .in and extending in vertically disposed position through the lower arm 17. The cutter spindle unit 20 includes a case 27 in which the cutter spindle 21 is journaled for movements bodily vertically upwardly and downwardly with the case as a unit. The upper end of the case has an upwardly extending follower point 28 which is vertically axially aligned with the cutter spindle 21. In this instance the case 27 with the cutter spindle 21 mounted .and journaled therein is continuously upwardly biased as a unit by a suitable biasing spring (not shown) in the .usual manner familiar in this art. As the specific construction of the cutterhead or spindle unit and the cutter spindle mounted therein and carried thereby forms no part specifically of my present invention, except insofar as such a unit is located and functions in the combination exemplified herein, it is not believed necessary to make any detailed .disclosure thereof. Such cutterhead and spindle units are known to the art and are in use, being exemplhied in such US. patents as Nos. 1,562,237, 1,956,505, 1,959,269, 2,900,838, 2,557,876, 2,645,161, and 2,658,423.

In this particular example a slider head identified generally by the reference character H and of generally elongated form, is suitably mounted in position on the upper end of column C and on and longitudinally along the neck N, as by bolting such slider head to the column and neck. The slider head H at the side thereof opposite the arm 10 on column C is provided with a vertical post member 18 extending vertically upwardly therefrom and having a hanger arm 19 extending horizontally from the upper end thereof over and spaced above the forward end of the slider head H on column neck N.

Thus the cutter spindle unit 20 mounted and carried on and by the links 14 and 15 is universally laterally horizontally swingable and such movements of the cutter spindle unit are effected by and under the control and dictation of the pantograph linkage P which, in turn, is power driven from the powered master unit M. The pantograph linkage P includes the parallel upper bars 30 pivotally coupled at their opposite ends to the adjacent ends of the parallel lower bars 31 thereof. The pantograph linkage P is pivotally hung and supported in horizontally disposed position from the underside of the hanger arm 19 by the pivot pin or stud 32 which is pivotally coupled with the usual slider block 33 on the adjacent upper bar 30 of the pantograph linkage. Thus mounted and hung, the pantograph linkage P is swingable in a horizontal plane about the pivot pin or stud 32. One of the lower bars 31 is extended outwardly across and above the slider head H to provide the out wardly and rearwardly extending tracer arm 34. Thus the pantograph linkage P is swingable on and about the pivot pin or stud 32 by the tracer arm 34. The cutter spindle assembly 20 and its mounting and supporting links 14 and 15 are pivotally coupled and connected with the pantograph linkage P by means of a slider block 35 slidably mounted on that lower bar 31 of the pantograph linkage which is parallel with the opposite lower bar 31 of which the tracer arm 34 is a continuation. The slider block 35 is pivotally coupled by means of a pivot pin or stud 36 with the upper arm 16 of the cutter spindle unit carrying link 15 which is positioned directly therebelow. The slider block pivot pin 35 is positioned in axial alignment with the cutter spindle 21 of the cutter spindle unit 20 mounted therebelow on arm 17 of link 15. Thus, universal lateral movements in its horizontal plane of the pantograph linkage P will correspondingly universally laterally swing the link 15 and the cutter spindle 21 of the cutter spindle unit 20 carried thereby over a work piece on the worktable T which may be positioned therebelow by the table.

The forming guide and powered spindle feed The forming guide G is in this instance mounted and supported in horizontal position attached to the underside of a forming guide holding plate 40 which, in turn, is attached at the inner end portion thereof to a mounting plate 41 extending horizontally forwardly from the upper end of a vertically disposed carriage 42. This carriage 42 is slidably mounted on spaced parallel vertical tie rods 43 for vertical movements upwardly and downwardly thereon. A bracket 44 is attached onto the upper side of the forward end of the slider head H and projects forwardly therebeyond to provide an upwardly offset head 45 through which the upper ends of the tie rods 43 extend and to which such rods are rigidly attached in fixed position depending downwardly therefrom. Thus the carriage 42, mounting plate 41, and forming guide G are vertically movable bodily as a unit assembly upwardly and downwardly on and constrained to a straightline path by said tie rods 43. In this instance the forming guide G is provided as a block having a convex undersurface G for slidable engagement by the follower point or pin 28 of the cutter spindle unit.

In the mounted and adjusted position of the forming guide G, as supported from the bracket 44, the forming guide lies directly over the cutter spindle unit 20 with the upwardly extending follower point 28 of the latter unit biased into slidable engagement with the undersurface G of the forming guide. Thus, as the cutter spindle unit 20 is universally laterally moved over a work piece by the pantograph linkage P, the depth of feed of the '7 cutter spindle 21 of unit 20 into a work piece is determined by the vertical position of the forming guide G and thecontour of the undersurface G. With the cutter spindle unit 29 continuously upwardly spring biased, it follows that upward movement or raising of the forming guide G by its carriage 42 will result in upward following movement of the cutter spindle unit 20 to thus witl'idraw'or retract the cutter spindle 21 from its downwardly fed working position in the work piece. Conversely, with the forming guide G in its raised positions, downward movement therof will force the cutter spindle unit 20 downwardly and thus feed the cutter spindle 21 of the latter unit downwardly to its downv position relative to the worktable T and a work piece thereon.

By my present invention I provide powered means for bodily raising or lowering the carriage 42 on the tie rods 43 to thus raise or lower the forming guide G and effect retraction or downfeed of the cutter spindle unit 20 and cutter spindle 21. In this instance I provide such powered means as of the pressure fluid actuated type, specifically inthis example air under pressure. As will be hereinafter referred to and explained, such powered cutter spindle feed means is interrelated and interlocked in the cycle of the powered master unit and of the machine organization of which it forms a major component' in such a manner that the cutter spindle unit 20 and its cutter spindle 21 are retracted or withdrawn upwardly from working position automatically upon completion of the profile milling cycle and are fed downwardly automatically to the work piece at the start of the profile milling cycle. The powered feed for the forming guide carriage 42 and the forming guide G by which feed of the cutter spindle unit 20 is obtained is in this example in the form of an air cylinder and piston unit 50 which includes a cylinder 51' having a-piston 52 reciprocal therein with a piston rod 53 extending through the usual gland at one end of the cylinder. Compressed air intake-exhaust ports 54 are provided through a side wall of the cylinder unit in locations at opposite sides of the piston 52, so that this cylinder and piston unit 50 is of the conventional double-acting type familiar in the art by which selectively controlled directional movement of the piston and its rod 53 may be obtained. A cylinder unit mounting plate 55 is attached and secured in' horizontally disposed position to and across the lower ends of the tie rods 43. The cylinder and piston unit 50 is attached at its piston rod end to this plate 55 with the cylinder 51 depending therefrom. The piston rod 53 extends upwardly to and is connected at its upper end with the forming guide carriage 42 at the lower end of that carriage. Thus, upward movement of the piston 52 and rod 53 raises the carriage 42 with forming guide G while the reverse, downward movement of the piston and piston rod moves the carriage 42 with forming guide G downwardly to thereby downwardly feed the cutter spindle unit 20 and its cutter spindle 21 to the down position-thereof relative to the worktable T and a work piece thereon.

The air cylinder and piston unit 50 is selectively controlled in its operation by a solenoid actuated control valve unit 56 which may be of any of the usual four-way valve types familar in the art. The valve unit 56 is operatively coupled with the ports 54 of cylinder 51 of the unit 50 by the pipe lines 57, respectively. The unit The powered master unit Th'e master unit. M which is power. driven and connected with the pantographlinkage P is mounted at the rear or outer end portion of the slider head H and in the form thereof of this example includes a master plate 69 mounted in horizontal position on a slide plate 61 which is mounted and supported on the slider head H. master plate 60 is adjustably mounted on the slide plate 61 for movements thereon independently thereof in either direction along a straight-line path longitudinally of the slider head while the slide plate 61 is adapted for movements in either direction along a straight-line path transversely relative to the slider head to move the master plate 60 bodily with it to adjusted positions, Thus the master plate 60 is mounted for cross-compound movements for positional adjustment relative to the pantograph linkage P and the cutter spindle unit 20. Any suitable means may be used for releasably securing the master plate 60 and slide plate 61 in an adjusted position, such, for example, as the bolts 62 in the parallel elongated slots 62a in the master plate.

The master plate 60 is provided with a master profile forming recess or pocket 63 therein which provides by the surrounding edge wall thereof formed by the body of the plate 60, the endless master profile surface 64 in planes normal or at angles to the plane of the plate; The master profile surface 64 is formed on the master plate as a precisely scaled enlargement of the contour of the surface which is to be profile milled on a work piece by the cutter spindle 21 of the cutter spindle unit 20. In this instance the master profile surface 64 provides a continuous and unbroken surface completely around and surrounding the recess or pocket 63 in the master plate.

The tracer stylus assembly S of the master unit M is power driven in tracing engagement with and around the master profile 64 and is connected with the tracer arm 34 of the pantograph linkage P in a manner to be hereinafter explained. The tracer stylus assembly S is movably mounted and carried on a holder assembly 65 which is power rotated on and about an axis normal to the plane of the master plate 61, and which is preferably an axis about which the non-symmetrical endless profile surface 64 may have been generated. In this specific example this holder assembly 65 includes a case or housing 66 fixed to the upper end of a shaft or spindle 67 which extends in vertically disposed position through the base plate 60 within and at a location centrally of the profile recess or pocket 63. The shaft 67 is journaled in the master plate 60' for rotation about an axis normal to the master plate, in this instance a vertical axis, by thevertically spaced annular sets of anti-friction bearing assemblies 67a. The case 66 of the tracer stylus holder assembly 65 is thus mounted in horizontally disposed position on and fixed to the upper end of the shaft 67 extending, radially in opposite directions thereacross for rotation within the master recess 63 by power applied to the shaft 67. The case 66 has a length less than the minimum width or minimum diameter of the master recess 63 so that it may be freely revolved within the recess around the axis provided by the shaft 67 with its opposite ends spaced from and clear of the master profile surface 64. V p

A driver rod 68 is mounted in position extending longitudinally through and centrally of the case 66 by a linear or slide bearing assembly 69 mounted within the case 66 intermediate the opposite ends thereof. The driver rod 68 has a length substantially greater than the length of the case 66 and is freely reciprocal through the case in the bearing assembly 69, suitable apertures being provided in the opposite end walls 66a and 66b for freely slidably receiving the driver rod thereth-rough. A cross-head 70 is attached to and across one end of the driver rod 68. Spaced, parallel guide rods 71 are fixed at their outer ends in the crosshead 70 spaced equal distances from opposite sides, respectively, of the driver rod 68. These actuator rods 71 extend inwardly from and -are freely received at their inner end lengths in spring mounting chambers 72, respectively, formed or provided in the case 66. An expansion spring 73 of the coil type is mounted and confined in each chamber 72 over and around the rod 71 in that chamber in engagement at its inner end against the inner end wall formed across the chamber and at its outer end being engaged against the inner side of the crosshead 70. By this arrangement and construction the driver rod 68 is continuously yieldingly biased and projected in a direction outwardly, from the case 66 of the holder assembly 65. The driver rod 68 and its crosshead 70 may be forced inwardly of the case 66 by forces applied thereto to overcome the biasing forces exerted thereon by the springs 73.

The tracer stylus assembly S, in this instance, comprises a tracer pin 75 which is rotatably mounted and journaled in and extending through the crosshead 70 along the axis line of the driver rod 68 and with the axis of the pin 75 intersecting and normal to a projection of the axis of the driver rod. The tracer pin 75 extends a distance below crosshead 70 and mounts rotatably thereon a stylus roller 76 concentric with the axis of the tracer pin and in position spaced a slight distance above the lower end 75a thereof. This lower end 75a of the tracer pin 75 is preferably rounded for a purpose appearing hereinafter. The tracer pin 75 is mounted in the driver arm 68 with the stylus roller 76 opposite or in line with the master profile surface 64 so that the springs 73 in the holder assembly 65 bias the driver rod 68 with the tracer pin 75 outwardly to yieldingly maintain the stylus roller S in rolling and tracing engagement with the master profile surface. Thus rotation of the shaft 67 rotates the holder assembly 65 and the driver rod 68 and tracer pin 75 around the axis of the shaft 67 with the stylus roller 76 moving around and yieldingly maintained in tracing engagement on the master profile surface 64. As the stylus roller 76 moves around the master profile the driver rod 68 and tracer pin 75 move inwardly and outwardly radially of the axis of rotation of the holder assembly 65 in accordance with the radial distances presented at any point around the master profile surface 64 between the master profile and the axis of rotation of the shaft 67, that is, in accordance with the profile presented by the master pro-file surface.

The tracer pin 75 extends vertically upwardly a distance above the crosshead 70 and is connected to the outer end of the tracer arm 34 of the pantograph linkage P. The outer end of the tracer arm 34 is provided with a suitable bore transversely therethrough into and through which the upper end length of the tracer pin 75 extends and in which it is fixed to the tracer arm. If desired or found expedient, the outer end of the tracer arm 34 may be provided with the vertically disposed sleeve 34:: providing a bore therethrough for receiving and into which the tracer pin 75 extends and is secured. The tracer pin 75 in position connected with the tracer arm 34 has its axis located on and intersecting a projection along tracer arm 34 of the axis line passing through the pivot axes of the pivotal coupling of the upper bars 30 to that lower bar 31 of which the tracer arm forms an extension. Thus movements of the tracer stylus S around the master profile surface 64 by rotation of the tracer stylus holder assembly 65 while yieldingly maintained in contact with the master profile surface by springs 73 will cause the tracer stylus to move inwardly and outwardly as it traces around the non-symmetrical master profile 64. Such movements of the tracer stylus S as dictated by the master profile surface are transmitted by the tracer pin 75 to the tracer arm 34 and through the pantograph linkage P to the cutter spindle unit 20 and its cutter spindle 21 as movements of the cutter spindle in precise and scaled reproductions of the movements of the tracer stylus in following around the master profile surface 64 in engagement therewith.

Powered drive of the master unit The tracer stylus holder assembly 65 is power driven by powered rotation of the driving shaft 67 from the motor MM. The motor MM is mounted and supported in horizontally disposed position by a bracket structure 77 which in this instance is attached to the underside of the master plate 60 to provide the depending vertically disposed mounting plate 77a having the outwardly ex-' tending arm 77b to the outer side of which the motor MM is suitably bolted and attached. The motor MM is mounted on the plate 77b in position with the driving shaft 78 of the motor horizontally disposed.

A variable speed transmission unit 80 is suitably mounted and attached on the outer side of the mounting plate 77:: of bracket structure 77. The transmission unit 80 is provided with the horizontally disposed power input shaft 81 which is coupled in driven relation with the driving shaft 78 of motor MM by a suitable coupling unit 81a. A bracket 82 is attached to the master plate 60 in position depending therefrom at the inner side of the variable speed transmission unit 80, that is, at the side thereof opposite motor MM. This bracket 82 provides a horizontally disposed casing or housing 83 which jour nals therein a driven worm shaft 84 in horizontally disposed position in axial alignment with the power output or take-0E shaft 85 of the variable speed transmission unit 80. This power take-off shaft 85 is connected in driving relation with the worm shaft 84 by a suitable coupling 86. A worm 87 is mounted on the worm shaft 84 within the housing 83. A shaft 88 is journaled in vertically disposed position in the housing 83 and extends a distance upwardly from that housing as the driving or power input shaft of an electromagnetic clutch unit which is mounted and supported from the master plate 60 in position directly below the driving shaft 67 of the tracer stylus holder assembly 65. The driven shaft of the clutch unit 90 is constituted and provided by the shaft 67 of the tracer stylus holder assembly 65 or as the case may be, is connected with and forms a continuation of shaft 67. The driven component of the clutch unit 90, that is to say, the shaft 67 in this instance, is in axial alignment with the shaft 88 that is journaled in the housing 83 of the bracket 82. A worm wheel 89 is mounted on the shaft 88 in constant driven mesh with the worm 87 and the worm shaft 84.

The electromagnetic clutch unit 90 may be of any of the types familiar to the art suitable for and adapted to operation in the combination of the powered drive of the transmission of this example machine, for the purpose of clutching or engaging the power driven shaft 88 with the driving shaft 67 of the tracer stylus holder assembly 65 or of declutching and disengaging the power driven shaft 88 from the shaft 67 for free rotation of the latter shaft and the tracer stylus holder assembly 65 and tracer stylus S thereof independently of the powered drive. The clutch unit 90 includes the usual actuating electromagnet or solenoid CS. The actuating electromagnet or solenoid CS is shown schematically in electrical connection in its control circuit in the control Circuit diagram of FIG. 8 of the drawings. Beyond such schematic showing of the actuating solenoid and the general disclosure of the clutch unit 90 it is not considered necessary herein to make a specific structural disclosure in view of the fact that any of the suitable well-known electromagnetic clutches may be used as the component in the combination of this example embodiment of the invention. Sufiice it to state that when the control circuit through the solenoid CS is closed to energize the solenoid such energized solenoid actuates the clutch to engage the shaft 67 in driven connection with the powered shaft 88 and when the solenoid CS is deenergized, declutching actuation of the clutch unit 90 is eifected to disconnect the shaft 67 and the tracer stylus holder assembly 65 from the powered transmission drive therefor.

Tracer stylus and cutter spindle positioning for cutter spindle retraction from and feed to a work piece In accordance with the principles and features of my invention, I have provided a powered master unit, a pantograph linkage and a cutter spindle assembly combination by which undercut internal or external profile milling may be performed with automatic feed of an undercut milling cutter to and retraction thereof from milling engagement with a work piece. In carrying out this feature in the present example the tracer stylus S is moved inwardly from tracing engagement with the master profile surface 64 to an inactive position with simultaneous corresponding movement of the pantograph linkage P and the cutter spindle 21 of the cutter spindle unit 20 to position in which an undercut milling cutter on the spindle is spaced from and clear of the undercut profile milled into a work piece for free and unobstructed retraction of the cutter spindle and the milling cutter from the work piece. In carrying out these features of the invention in the instant example I provide in the master profile forming recess or pocket 63 of the master plate a spring biased, pivoted .gate or switch member 1 for engagement by the tracer roller 76 of the tracer stylus S for .switching or guided displacement of that stylus to an inactive position spaced from and out of tracing engagement with the master profile surface 64 upon the completion of a profile milling cycle. Such movement of the tracer stylus S simultaneously correspondingly moves the cutter spindle 20 and its cutter spindle 21 through the medium of the pantograph linkage P to a position from which the cutter spindle 21 and an undercut milling cutter thereon may be freely retracted or withdrawn vertically upwardly from the work piece. In 'order to efiect such displacement of the tracer stylus S by the gate member 100 I provide a retractor unit identified generally by the reference character R for engaging the tracer .stylus holder assembly '65 following the completion of a tracing cycle of the tracer stylus .8 around the .master profile 64, to reverse the direction of rotation of the tracer stylus holder assembly with the resulting guided displacement of the tracer st-ylus by the gate or switch 100 to an inactive or home position to thereby position the cutter spindle spaced from the work piece 7 forifree retraction of the cutter spindle from and feed thereof to the work piece.

In theform 'of this example, the gate or switch memher 100 includes a circular hub or base 101 which is rotatably journaled in a circular mounting recess 102 formed in the master plate 60 at a location-in the pocket or recess 63 spaced a distance inwardly from the master profile surface 64 between that surface and the shaft 67. The gate or switch member 100 includes a semi-circular or arcuateinner end portion 103 extending vertically .upwardly from and around the exterior surface at one side of the base 101 substantially concentric with the base and the outwardly and forwardly curved gate or switch plate 104 which extends across the master profile recess 63m and normally at its outer free end 105 engages against the adjacent surface of the master profile .64. The gate'member 100 is mounted'and positioned so that the gate orswitch plate 104 thereof curves and extends outwardly from the semi-circular inner end 103 thereof .on the base 101 in the direction of movement of the tracer stylus S through its power driven tracing cycle around the master profile surface 64, as will be clear by reference to FIG. 2 in particular. This gate member 100 is continuously biasedinto position with the outer .free end 105 thereof :engaged against the adjacent'por- .tion of the master 'profilesurface '64 by a spring unit .106 comprised of a retractile spring connected at one end to a fixed post 107 in the master profile recess 64 and at its opposite free end coupled to the adjacent end of theserni-circular portion 103 of the gate member 100 on the hub 101 by a suitable attaching pin 108'. Thus the gate member-1'00 is yiel'dingly' inwardly displaceable from engagement with the master P ofile 64 y engagement by the tracer rol er. 7. of; t e t ce y s S as e tracer ylus move in the cleclsv i d rec through its t ing cycle around the master profile 64. After the tracer roller 76 has moved past and, cleared the gate member 100, the biasing spring unit 106 returns the gate member to normal switching position engaging the master profile surface, 64. However, reverse movement, that is, movement countel's lockwise of the tracer stylus after the tracer roller 76 thereof has passed by and cleared the gate member 100, will cause the tracer roller to ride over the switch point 109 provided by the gate member into engagement with and along the switch plate which then guides the tracer roller and tracer stylus S inwardly to a position received on the hub or base 101 and within the semi-circular inner end 103 of the gate member which projects upwardly from such base.

The reverse or counterclockwise movement of the tracer stylus, S to its inwardly displaced, inactive position on the base 101 of the gate member is effected automatically in the powered master unit M of the present embodiment, by means of a retractor unit identified generally by the reference character R. This retractor unit R is mounted in position located on the upper side of the master plate 60 along one side of the master profile recess 63 and the tracer stylus holder assembly 65. Retractor unit R includes a tubular casing or barrel 110 mounted in fixed horizontally disposed position by the pedestal or mounting base 111 which is suitably fixed to the upper side of the master plate 60. A retractor rod 112 in the form of a tube member is reciprocally mounted in the barrel 110 and projects outwardly or forwardly therefrom. This retractor rod 112 is spring-loaded by a coil type retractile spring 114 connected at its inner end in fixed position in the barrel by an adjustable connector assembly 114a and at its outer end connected into the retractorrod by a suitable pin or connector 115. Thus the spring 1114 continuously acts to retract or telescope the retractor rod 112 into the barrel 110. The loading of the spring 114 may be adjusted as required by the adjustable connector assembly 114a. A retractor pin 116 is fixedin and extends radially outwardly from the inner side of the retractor rod 112 adjacent but spaced a slight distance inwardly from the outer end of the rod. This retractor rod has a length relative to the length or the barrel 110 such that in the normal, fully retracted position of the rod the retractor pil 116 projects inwardly across themaster profile surface 64 for a distance sumcient to lie in the path of and be engaged by the tracer pin 75 as the tracer stylus S completes its cycle around the master profile. However, the length of the retractor pin 116 is such that in the retracted position thereof its outer end is located clear of the gate member 153% so that the tracer pin 75 may freely move from its inactive or home position along the gate member to tracing engagement with thegmasterpmfilesurface 64 as a tracing cycle is started.

A contact button 117 is mounted 'adjustably in the router endv of the retractor; rod 112 in axial alignment with that rod. Amicroswitch 120 is mounted in fixed-position on the upper side of themaster plate 60 spaced outwardly thereon from the retractor unit R. The switch .120 includes an operating'plunger 121 which normally projects, outwardly therefrom on the side thereof facing the retractor ,unit with theplunger 121 in axial alignment with the retractor rod 112 and the contact button 11'! in the outer end thereof. This switch 120 is of the normally closed type withits operating plunger 121 in its normally outwardly projected position and isoperated to open position to open an electric circuit into which it is connected by depression of the operating plunger 121. The switch 120 is adapted to be actuated from its normal closed to its circuit opening position when the retractor rod 112 and contact button 117 thereon are projected from normally retracted positionof rod 112- toposition with the contact button 117 engaged with and depressing the switch actuating plunger 121. This switch 120 is a cycle controlling switch and is connected into a holding circuit of the control circuit to the solenoid CS of the clutch unit 90 for controlling the operation of that clutch to connect and disconnect the powered drive from the motor MM to the tracer stylus S, as will be described and explained in detail hereinafter.

A microswitch 122 of the multiple type for controlling two (2) circuits is adapted to be actuated to and maintained in position opening one circuit and closing the other circuit when the tracer stylus S is in its inactive or so-called home position on the base 101 of the gate member 100. In this specific example the switch 122 includes the operating plunger 123. The switch 122 is mounted in fixed position at the underside of the master plate 60 with the operating plunger 123 thereof extending vertically upwardly from the upper side of the switch in axial alignment with the hub or base 101 of the gate member 100. A spring loaded pin 124 is slidably mounted in an axial bore provided through the hub member 101 and the portion of the master plate 60 therebelow. The pin 124 is in engagement at its lower end with the outer end of the switch operating plunger 123 while a ball 125 is mounted and confined at the upper end of the pin 124 for depression to project the pin 124 downwardly to thereby depress the switch operating plunger 123 to operate the switch from position closing one circuit and opening the other to position opening the first-mentioned and closing the second-mentioned circuit. Upon release of the depressive forces on the ball 125 the spring loading of the pin 124 retracts the pin and releases the switch plunger 123 to permit the switch to restore to its normal condition. The ball 125 projects slightly above the surface at the upper side of the base 101 which provides the seat for the lower end of the tracer pin 75 when that pin and the tracer stylus assembly S are in home or inactive position thereon.

Thus, as the tracer stylus S is switched by the gate or switch member 100 from its normal tracing engagement with the master profile 64 to its inactive position on the base 101 of the gate member, the rounded lower end 75a of the tracer pin 75 engages and depresses ball 125 to thereby actuate the switch 122. As long as the tracer stylus S remains in its inactive position at the base 101 the switch 122 is maintained in the position thereof to which actuated by the depression of operating plunger 123. However, when the tracer stylus S is moved from its inactive position as it starts its next tracing cycle around the master profile 64, the end 75a of the tracer pin 75 moves from engagement with the ball 125 so that the switch 122 restores to its normal condition. As will be hereinafter referred to and explained in detail, the switch 122 is connected into the control circuit for the indexing mechanism for the worktable T so that such table may only be indexed when the tracer stylus S is in its inactive or home position withdrawn from the master profile 64 and the cutter spindle 21 is in position removed from the milled profile on the work piece for retraction of the cutter spindle. The switch 122 is also connected into the control circuit of the solenoid of the control valve unit 56 of the operating cylinder of the cutter spindle feed mechanism so that the feed mecha nism is caused to feed the cutter spindle downwardly when the tracer stylus moves from home position and to feed the cutter spindle upwardly when the tracer stylus moves to its home position.

With the tracer stylus in inactive position on the base 101 of the gate member 100, that is, position withdrawn from tracing engagement with the master profile 64, the retractor rod 112 is in its retracted position with the retractor pin 116 positioned removed from and clear of the path of movement of the tracer pin 75 as that pin, with the tracer stylus S, is moved from inactive position along the gate member 100 and across the switch point 109 14 into tracing engagement with the master profile surface 64. The tracer stylus holder assembly 65 is power driven from the motor MM through the shaft 67 and moves the tracer stylus S from its inactive or home position along the gate member 100 into tracing engagement at the switch point 109 with the master profile surface 64. The tracer stylus S then continues through its tracing cycle in the tracing direction around the master profile surface 64 by the powered rotation of the tracer stylus holder assembly 65. When the tracer pin 75 reaches the retractor pin 116, it engages such pin and thereby picks up the retractor rod 112 and withdraws this rod against the forces of the spring 114 until the contact button 17 is engaged with and operates the switch plunger 121 to open the circuit through switch 120 and thereby disengage the clutch unit to cut off power drive of the tracer stylus holder 65 and tracer stylus S. When the driving shaft 67 for the tracer stylus holder assembly 65 is disengaged from the power drive thereto, the retractor spring 114 instantly takes over and retracts the retractor rod 112 and the pin 116 against which the tracer pin 75 is engaged. Retraction of the pin 116 forces tracer pin 75 in the reverse direction and thus rotates the tracer stylus holder assembly 65 and the tracer stylus S in' a counterclockwise direction with the tracer stylus riding onto and along the gate member 104. The tracer stylus S is thus guided and withdrawn radially inwardly from the master profile surface 64 by the gate member against the forces of the springs 73 until seated on the base 101 within the semi-circular portion 103 of the gate member 100, that is, in the inactive or home position of the tracer stylus. As the tracer stylus holder assembly 65 with the tracer pin 75 and tracer stylus S are freely rotatable upon disconnection of the powered drive from the shaft 67, the momentum imparted thereto by the spring powered retraction of the retractor rod 112 will be sulficient to coast the assembly to its inactive position following disengagement of the pin 116 from the tracer pin 75. Such momentum imparted to the holder assembly 65 and tracer stylus S is sufiicient to overcome the biasing forces exerted by and to compress springs 73 in the holder assembly as the crosshead 70, tracer pin 75 and tracer stylus S are displaced radially inwardly by the inwardly curving track provided by the gate member 100.

As the retractor unit R moves the tracer stylus S and tracer pin 75 over and along the gate member 100, the crosshead 70 with the tracer pin 75 and the tracer stylus S are moved radially inwardly into the master recess 63 with resulting rocking or swinging of the tracer arm 34 which, through the pantograph linkage P, correspondingly swings and moves the cutter spindle assembly 20 with cutter spindle 21 and a milling cutter thereon away from the milled profile in a work piece. When the tracer stylus S reaches its inactive or home position on the gate member base 101 and comes to rest in that position, the cutter spindle 21 and an undercut milling cutter thereon will have been moved completely clear of the undercut milled surface on the work piece so that the cutter spindle and its milling cutter may then be withdrawn in a straightline vertically upwardly from the work piece. The tracer stylus S, cutter spindle 21 and a milling cutter thereon remain in such positions for cutter spindle and milling cutter retraction until the start of the next profile milling cycle. At the start of the next milling cycle and while the cutter spindle 21 and a milling cutter thereon are in their retracted position spaced from the surface of the work piece which is to be profile milled, the cutter spindle downfeed mechanism is operated to feed the cutter spindle downwardly to position opposite such surface of the work piece. The power drive of the tracer stylus holder assembly 65 in a clockwise direction is then started and the tracer stylus S is moved outwardly along and is guided by the gate member 100 into tracing engagement with the master profile surface 64. Such movement of the tracer "17 in the circuit line L21 through the rectifier 132 will be closed with the rectifier supplying direct current to the clutch actuating cylinder CS to thus engage the clutch unit 90 in connected driving relation with the driving shaft 67 of the tracer stylus holder assembly 65. When, however, the circuit through relay CR1 is broken, the set of contacts CR1 in line 21 will open and thus open the circuit through the rectifier 1-32 and deenergize solenoid CS of clutch unit 90 so that the clutch unit disengages from the shaft-67 and releases this shaft and the tracer stylus holder 65 for independent, free rotation.

A circuit line L22 is connected across circuit lines L10 and L11 and a table indexing control switch 133 is connected into this line L22. The switch is of the manually operable type in this example and is normally open. A solenoid IS is connected in the circuit line L22 between the switch 133 and the circuit line L11. This solenoid IS is a component of the operating mechanism for the indexing worktable T which controls the operation of the indexing motor IM to actuate the table T through an indexing step when the solenoid is energized. Thus, with the circuit line L22 closed, except for the switch 133, when the latter switch is manually closed by the operator, the solenoid IS is then energized and effects drive of the table T by the motor IM through the indexing step from one position of index to the next position of index.

A circuit line L23 is connected across circuit lines L10 and L11 and has connected therein a solenoid 58 which is the actuating solenoid of the control valve unit 56 which selectively controls the pressure fluid actuation of the cylinder and piston unit 50. When the solenoid 58 is energized, the valve unit V is set for pressure fluid actuation of the piston rod 53 downwardly to feed the cutter spindle to position at the work piece and when this solenoid IS is deenergized, the control valve .unit 56, which is of the usual four-way type familiar in the art in various forms thereof, is caused to actuate to position reversing the fiow of pressure fluid to the cylinder and piston unit so that the piston rod 53 of that unit is then moved upwardly to effect retraction of the cutter spindle from the work piece.

The switch 122 which is mounted on the master plate 60 and which is operated by the tracer stylus S when the tracer stylus is in its inactive or home position, is connected into both the circuit line L22 and the circuit line L23. The switch 122 includes the contacts 1 and 2 in circuit line L22 and the contacts 3 and 4 in circuit line L23. A movable contact arm 5 is operable to open and close the circuit line L22 across the contacts 1 and 2 while a movable switch arm 6 is operable to-open and close the circuit line L23 across the contacts 3 and 4. These switch arms are interlocked mechanically, as indicated by the dotted line 7, and are set so that when arm 5 is in circuit closing position across contacts 1 and 2, the switch arm 6 is in circuit opening position across contacts 3 and 4, and when arm 5 is in circuit opening position switch arm 6 is in circuit closing position across contacts 3 and 4. The switch 122 normally is positioned with the arm 5 thereof open across contacts 1 and 2 to open a circuit through circuit line L22 with the arm 6 thereof closed across contacts 3 and 4 to condition circuit line L23 for the closing of a circuit therethrough to energize the solenoid 58 of the cutter spindle downfeed mechanism F. The switch 122 includes the operating plunger 123 which, when depressed, actuates the switch to position with arm 5 thereof closed across contacts 1 and 2 and arm 6 thereof open across contacts 3 and 4 in the circuit line L23. When the depressing forces are removed from the switch operating plunger 123, the switch restores switch arm 5 to open position with switch arm 6 then in closed position.

Summary of operations A machine of the example embodiment is conditioned for performing the intermittent, manually initiated automatic profile milling cycles by closing the momentary contact, main start switch SW with the main stop switch SS in closed position. Closing of the main start switch SW activates the contactor M1 which in turn closes the sets of normally open contacts M1 in the branch power lines L4, L5 and L6 to the cutter spindle driving motor SM, the master unit driving motor MM and the indexing table driving motor IM. These motors are thus started in operation and continue in operation throughout the intermittent automatic profile milling cycles until the machine is shut down by opening the main stop switch SS. Activation of contactor M1 also closes the set of contacts M1 in circuit line L10 and thus conditions the control circuit network for control operations thereof.

If operation of the coolant system is required, the operator closes the normally opened coolant switch SC which closes circuit line L16 and activates the contactor M2 to thereby close the sets of contacts M2 in the branch power lines L7, L8 and L9 to the coolant pump motor CM. If operation of the coolant system is not required or operation is to be stopped, the switch SC is operated to open circuit line L16.

The profile milling operations are started from a position of the machine in which the tracer stylus S is in its inactive or home position on the base 101 of the gate member spaced from the master profile surface 64. In this inactive position of the tracer stylus S the cutter spindle 21 is, of course, in retracted position but has also been moved laterally by the pantograph linkage P to a position axially aligned with its inactive position when fed downwardly to a work piece W on the table T (see FlG. 10). An under-cutting profile milling cutter PC is mounted in the usual manner on the lower end of the cutter spindle 21. With the tracer stylus S in its inactive position as above defined, the lower end 7501 of the tracer pin 75 is engaged with and depresses the operating plunger 123 of the switch 122 to condition that switch with the arm 5 thereof closed across contacts 1 and 2 in circuit line L22 and with the arm 6 thereof open across contacts 3 and 4 in circuit line L23 to open the circuit through the downfeed solenoid 58. The retractor operated switch is in closed position closing the holding circuit line L20 through the relay CR1. The cycle start switch is open so that the circuit through the relay CR1 is open with the set of contacts CR1 in the circuit line L21 open through the rectifier 132. Thus, the clutch actuating electromagnet or solenoid CS of the clutch unit '90 is deenergized with the clutch in position disengagedfrom driving connection with the driving shaft 67 of the tracer stylus holder assembly 65.

If, before starting an automatic profile milling cycle, it is necessary to index a work piece W on the worktable T to a working position for profile milling engagement by the milling cutter PC, the operator manually closes the table indexing switch 133. As the switch 122 is then in position closing the circuit line L22, the closing of the index switch 133 will complete the circuit through the solenoid IS of the table indexing mechanism and efiect indexing operation of that table through one indexing step to therebyposition a work piece W in the required workingposition. The cutter spindle 21 and the milling cutter FC thereon are in retracted or withdrawn position raised from the worktable T and a work piece W thereon. Such retraction of the cutter spindle 21 was effected by the cylinder and piston unit 50 to raise the forming guide assembly G to thus efiect retraction of the cutter spindle automatically at the conclusion of the last profile milling cycle performed by the machine.

With the work piece W indexed to working position, the machine may then be started into an automatic profile milling cycle for milling out on the work piece W the undercut profile contour or groove 64W on the work piece W. The automatic profile milling cycle is initiated by the operator manually closing the momentary contact, cycle start switch 130. When the cycle switch 130 is closed, the relay CR1 is activated with the set of contacts CR1 being closed to close the circuit through the rectifier 132 with resulting supply of direct current to and energization of the clutch solenoid CS of the clutch unit 90. The clutch unit is thus instantly clutched to engage the shaft 67 to move the tracer stylus holder 65 and the tracer stylus S in a clockwise direction. During this period in the cycle the retractor unit operated switch 120 is, of course, closed in the holding circuit line. L20 so that the circuit relay CR1 is activated. At this time the switch 131 in the circuit line L19 is closed with the worktable T in the position to which indexed.

With the engagement of the clutch unit 90' and the rotation in a clockwise direction of the shaft 67 through the powered drive transmission from the master motor MM, when the end 75a of the tracer pin 75 moves from the switch actuating ball 125, the switch 122 is instantly actuated to open the circuit line L22 through the index solenoid IS by the arm 5 with the switch arm 6 then being moved to closed position across the contacts 3 and 4 to thereby close circuit line L23 and energize the cutter spindle downfeed solenoid 58. The energizing of solenoid 58 sets the valve control unit 56 of the cylinder and piston unit 50 in position for pressure fluid actuated downward movement of the piston rod 53 and the forming guide G attached thereto. Thus the cutter spindle 21 and the milling cutter FC thereon are fed down to their lowered position at a work piece W, such lowered or down position of the cutter spindle and milling cutter being shown in FIG. 1. During the downfeed of the cutter spindle by operation of the cylinder and piston unit 50, the tracer stylus holder assembly 65 is being driven clockwise with the tracer stylus S spring biased yieldingly into engagement against the gate member 100. As the tracer stylus S is moved outwardly along the gate member 100, the tracer stylus is guided thereby into position with the tracer roller 76 of the tracer stylus in rolling tracing engagement with the master profile surface 64. The movement radially or laterally outwardly of the tracer stylus S correspondingly moves the cutter spindle 21 and the milling cutter PC thereon into position with the milling cutter in milling engagement with the Work piece W by the time the tracer roller 76 of the tracer stylus S has reached and crossed over the switch point 109 of the gate member 100 and into tracing engagement with the master profile surface 64. The tracer stylus S is then power driven by the motor SM around and in tracing engagement with the master profile surface 64. During the milling cycle the forming guide G is pressure locked by the cylinder and piston unit 50 in its down position to thereby hold the cutter spindle 21 and its milling cutter FC in the required down position, but with the cutter spindle universally laterally movable relative to the forming guide.

When the tracer stylus S has moved around and through its tracing cycle to the gate member 100, the tracer roller 76 engages against and forces itself past the gate member with the latter member yielding radially inwardly against the forces of its biasing spring 106. The tracer stylus S thus uninterruptedly continues through its tracing cycle for a distance past the gate member 100 with the gate member restoring to its normal position under the action of spring 106 as soon as the tracer stylus has cleared. However, when the tracer stylus S reaches the gate member 100', the tracer pin 75 engages against the retractor pin 116 on the retractor rod 112. After picking up the tracer pill 116 the tracer stylus S continues its tracing movements in the clockwise direction without interruption under the power drive from the motor MM. The continued power driven movement of the tracer stylus S past the gate member 100 withdraws and extends the retractor rod 112 from its retracted position within barrel R against the forces of the spring 114 until the contact button 117 at the outer end of the retractor rod engages the switch operating plunger 123 of the rnicroswitch 120.

When the tracer stylus S'has moved around the master profile surface 64 to a point where the contact button 117 of the retractor rod 112 engages the switch actuating plunger 123, the depression of the latter plunger opens the switch 120 in the holding circuit line L20 and thus instantly drops out or inactivates the relay CR1 which thus eifects opening of the sets of relay contacts CR1 in the circuit line L20 and in the circuit line L21. Opening of the contacts CR1 in circuit line L21 opens the circuit through the clutch solenoid CS of the clutch unit and thus effects operation of the clutch unit to declutch and disconnect the driving shaft 67 from the powered 'drive transmission from the motor MM. Instantly upon the disconnection of shaft '67 from its powered drive, this shaft with the tracer stylus holder assembly- 65 and the tracer stylus S are released for free rotation thereof in either direction and the retractor unit R then takes over and under the action of the spring 114 moves the tracer stylus S in the reverse or counterclockwise direction onto and along the gate member with the gate member guiding and forcing the tracer stylus radially inwardly to the base 101. In this particular example the retractor pin 116 of the retractor unit R disengages from and releases the tracer pin 75 of the tracer stylus S at an intermediate point along the gate member 100 before the tracer stylus S reaches its inactive or home position on the gate member base 101. The tracer stylus S, rotating with it the holder assembly 65 and the shaft 67, moves to inactive position on the base 101 under the impetus imparted thereto by the retraction of the spring loaded rod 112 of the retractor unit R. The tracer stylus S is stopped and brought to rest when it reaches inactive position on the base 101 by the curved base portion 103 of the gate member which forms a stop barrier in the path of the tracer stylus.

During the tracing cycle the milling cutter PC is in undercut profile milling engagement with and around the work piece W to mill therein the undercut groove or recess 64W. The profile of the groove 64W is accurately and precisely determined by and is a reproduction of the master profile surface 64 through the operation of the pantograph linkage P which couples the cutter spindle 21 and the milling cutter FC mounted thereon with the tracer stylus S. Following the completion of the milling cycle the movements of the tracer stylus S in the reverse direction and radially inwardly from the master profile surface 64 under the guidance of the gate member 100 to position on the gate member base 101, are transmitted by the pantograph linkage P as precisely corresponding movements of the cutter spindle 21 and a milling cutting thereon. Hence, when the tracer stylus S reaches and comes to rest at its inactive position, the cutter spindle 21 and milling cutter FC thereon will be displaced radially inwardly to a corresponding inactive position clear of and spaced from the undercut profile milled surface of a work piece, say, for example, the milled groove 64W of work piece W. With the cutter spindle and milling cutter in such inactive position completely clear of the undercut profile mill in and unobstructed by the work piece, the cutter spindle and milling cutter may be freely withdrawn to retracted position and may be as freely fed downwardly from retracted position to such inactive or down position at the work piece.

When the tracer stylus S reaches and comes to rest in its inactive or home position on the hub 101 of the gate member 100, the rounded lower end 75:: of the tracer pin 75 engages and depresses the ball which is mounted in the base 101 and thus depresses the switch operating plunger 123. The depression of switch plunger 123 actuates the switch 122 to move arm 5 thereof across and closing the contacts 1 and 2 in line L22 and to move arm 6 thereof to open position across the contacts 3 and 4 in the circuit line L23. The opening of circuit line L23 deenergizes the solenoid 58 of the control valve unit 56 of the cylinder and piston unit 50. Deenergization of the solenoid 58 causes the control valve unit 56 to operate to position in which the pressure fluid is directed to and from the cylinder unit 50 to force the upward displacement of the piston rod 53 and thus efiect withdrawal of the cutter spindle 21 and a milling cutter thereon to retracted position above the work piece.

The closing of circuit line L22 by switch 122 conditions the circuit to solenoid IS of the table indexing mechanism for closure by manual operation of the indexing switch 133 in the line L22. The switch 131 is a normally closed interlock switch in the circuit line L19 of the control circuits for the electromagnetic clutch unit 90. However, when switch 133 is closed for operation of table T through an indexing step, switch 131 is open to prevent operation of the machine in a milling cycle. Switch 131 closes when the table T comes to rest in its position of index.

With the machine at rest with the tracer stylus S at its inactive position on the base 101 of the gate member 109 and with the cutter spindle 21 withdrawn or retracted to position spaced above the worktable T and a work piece thereon, the operator may index the worktable, if desired, to position a new work piece at a working station for profile milling thereof by the next milling cycle of the machine. When the switch 120 was opened by the retractor unit R at the end of the profile milling cycle to thereby shut off the powered drive of the tracer stylus, the circuit relay CR1 was dropped out so that not only was the control circuit line L21 of the clutch solenoid CS opened, but also the holding circuit line L20 was opened by the opening of the contacts CR therein. However, instantly following the counterclockwise movement of the tracer stylus S by the retractor unit R and the withdrawal of the retractor rod 112 from position depressing the operating plunger 123 of the switch 120, this switch restores to its normal closed position thereby conditioning the control circuits of the clutch solenoid CS for closing and energization of that solenoid by manual operation of the cycle start switch 120 to close that switch. When cycle start switch 130 is closed, the power drive of the tracer stylus S is started so that the stylus moves in a clockwise direction from its inactive position on the base 101. As the tracer stylus S moves from the base 1&1, it disengages from the switch operating ball 125 so that the switch 122 restores to position opening circuit line L22 to the index solenoid IS and closing the circuit line L23 to the solenoid 58 of the cylinder and piston unit 50 of the cutter spindle feed mechanism.

Instantly upon the closing of circuit line L23 by the switch arm 6 of switch 122 the control valve solenoid 58 is energized and effects operation of the cylinder and piston unit 59 to draw or feed the cutter spindle 21 and the milling cutter FC thereon downwardly to their down position relative to a work piece W on the table T for subsequent movement radially outwardly to place the milling cutter into milling engagement with the work piece. This feed of the cutter spindle and milling cutter to the down positions thereof is completed during the period of the movement of the tracer stylus S along the gate member 160 so that the cutter spindle and the milling cutter are in the down position by the time the tracer stylus reaches and passes over the switch point 109 of the gate member and into tracing engagement with the master profile surface 64. Thus, as the tracer stylus S moves into tracing engagement with the master profile surface 64, the cutter spindle 21 and the milling cutter PC thereon are moved correspondingly by the pantograph linkage P to engage the milling cutter into milling engagement with the work piece W for milling the undercut profile surface or groove 64W on and around the work piece under the control and dictation of the tracer stylus S as the tracer stylus is power driven in the clockwise direction around and in tracing engagement with the master profile surface 64. As the work piece is being milled according to master profile surface 64, the form ing guide G adds a vertical component to the cutter movement.

In the foregoing manner the automatic profile milling cycles are performed by the machine with the machine automatically stopping operation upon the completion of each cycle as determined by the cycle limit switch 120, and with the tracer stylus S and the cutter spindle then being automatically moved to their inactive positions by reversal of the direction of the movements thereof by the retractor unit R and the cutter spindle being automatically retracted from its down position. With the machine at rest with the tracer stylus S and the cutter spindle and milling cutter in their inactive positions, the completed work piece may be removed from the worktable T. The table may then be indexed, if necessary, and the next profile milling cycle commenced by the operator pressing the cycle start switch 130, whereupon the tracer stylus is power driven from inactive position to tracing engagement with the master profile surface and the cutter spindle is both fed to its down position and moved laterally automatically to engage a milling cutter thereon with the work piece as the tracer starts into and is then power driven through its tracing cycle.

The powered master unit disclosed and claimed herein in the profile milling machine combinations and sub-combinations hereof, is not claimed herein per se, but is disclosed and claimed in my copending application filed August 6, .1956, as a division of this application.

It will also be evident that various other changes, modifications, designs, constructions, additions, substitutions, eliminations and combinations and subcombinations may be resorted to without departing from the broad spirit and scope of my invention, and hence I do not desire or intend to limit or restrict my invention to the exact and specific forms and embodiments of the example hereof, except as may be required by any specific and intended limitation thereto appearing in any of the claims hereto appended.

What I claim is:

1. In a profile milling machine, in combination, a supporting structure; a worktable; a cutter spindle mounted for universal lateral movements over said worktable; said cutter spindle being also mounted for movements axially between a working position at said worktable and a non-working position retracted therefrom; powered feed mechanism operatively connected with said cutter spindle for feeding said spindle from non-working position to working position and for retracting said spindle from working to non-working position; a powered master unit on said supporting structure; said master unit including a profile surface thereon, a tracer stylus mounted for movements in tracing engagement along said profile surface and for movements radially relative thereto between a position in tracing engagement therewith and an inactive position spaced radially therefrom, and a powered drive mechanism for moving said tracer stylus along said profile surface in tracing engagement therewith through a tracing cycle; a pantograph mechanism pivotally supported on said supporting structure connected between said tracer stylus and said cutter spindle for transmitting movements to said cutter spindle as lateral movements thereof in scaled reproduction of the movements of said tracer stylus; means operable upon completion of a tracing cycle of said tracer stylus for moving the latter radially from position in tracing engagement with said profile surface to inactive position and through said pantograph mechanism simultaneously moving said cutter spindle laterally to position for retraction from working to non-working position; and interlock means for effecting operation of said cutter spindle feed mechanism to retract said cutter spindle when said tracer stylus is moved to inactive position upon completion of a tracing cycle.

2. In a profile milling machine, in combination, a sup porting structure; a worktable; a cutter spindle mounted for universal lateral movements over said worktable and being also mounted for movements axially between a working position at said worktable and a retracted position removed therefrom; a powered master unit mounted on said supporting structure; said master unit including a profile surface thereon, a tracer stylus mounted for movements in either direction along said profile surface and being also mounted for movements radially relative to said profile surface between tracing engagement therewith and an inactive position spaced radially therefrom, and powered drive mechanism for moving said tracer stylus in one direction along said profile surface through a tracing cycle; a pantograph linkage connecting said tracer stylus and said cutter spindle for transmitting movements of said tracer stylus to said cutter spindle; powered means for releasably engaging and moving said cutter spindle in the direction reverse of the direction of tracing movement thereof to an inactive position spaced radially from and out of tracing engagement with said profile surface upon completion'of the tracing cycle to simultaneously move said cutter spindle through said pantograph linkage to position for retraction of said cutter spindle from said worktable; and said powered means for moving said tracer stylus in the reverse direction being operable to disengage from and release said tracer stylus when the latter reaches said inactive position.

3. In a profile milling machine, in combination, a supporting structure; a worktable; a cutter spindle mounted for universal lateral movements over said worktable; said cutter spindle being also mounted for movements axially thereof between a working position at said worktable and a non-working position retracted therefrom; powered feed mechanism operatively connected with said cutter spindle for feeding said spindle from retracted non-working position to working position and for retracting said spindle from working position to non-working position; a powered master unit on said supporting structure; said master unit including a profile surface thereon, a tracer stylus mounted for movements in either direction along said profile surface and being also mounted for movements radially relative to said profile surface between a position in tracing engagement therewith and an inactive position spaced radially therefrom, and a powered drive mechanism for moving said tracer stylus along said profile surface in one direction in tracing engagement therewith through a tracing cycle; movement transmitting mechanism connected between said tracer stylus and said cutter spindle for transmitting movements of said tracer stylus to said cutter spindle as lateral movements of the latter; and means operable by said tracer stylus upon completion of a tracing cycle for moving said tracer stylus redially to inactive position and through said pantograph mechanism simultaneously correspondingly moving said cutter spindle laterally to position for retraction from working position to non-working position by said powered feed mechanism. 7

4. In a profile milling machine, in combination, a supporting structure; a worktable; a cutter spindle mounted for universal lateral movements over said worktable; a powered master unit on said supporting structure; said master unit including a profile surface thereon, a tracer stylus mounted. for movements in either direction along said profilesurface and being also mounted for movements radially relative to said profile surface between a position in tracing engagement therewith and an inactive position spaced radially therefrom, a powered drive mechanism releasably engageable with said tracer stylus for moving the latter along said profile surface in one direction in tracing engagement therewith through a tracing cycle, and means for connecting said powered drive mechanism with and for disconnecting said powered drive mechanism from said tracer stylus; movement transmitting mechanism connected between said tracer stylus and said cutter spindle for transmitting movements to said cutter spindle as lateral movements thereof corresponding to movements of said tracer stylus; independent powered means operable upon completion of a tracing cycle of said tracer stylus for moving the latter in the direction reverse to the direction of movement thereof through a tracing cycle and radially to inactive position relative to said profile surface and simultaneously through said movement transmitting mechanism moving said cutter spindle laterally; and interlock mechanism operable by said tracer stylus for elfecting operation of said means for connecting and disconnecting said powered drive mechanism to disconnect said powered drive mechanism from said tracer stylus when the latter completes a tracing cycle.

5. In a profile milling machine, in combination, a supporting structure; a cutter spindle mounted for universal lateral movements over said worktable and being also mounted for movements axially thereof between a working position at said worktable and a non-working position retracted therefrom; powered feed mechanism for moving said cutter spindle between working position and nonworking position; a master unit including a profile surface thereon, a tracer stylus mounted for movements in either direction along said profile surface and for movements radially relative thereto between tracing engagement therewith and an inactive position spaced radially therefrom, and powered drive means for moving said tracer stylus in one direction along said profile surface in tracing engagement therewith through a tracing cycle; movement transmitting mechanism connecting said tracer stylus and said cutter spindle for transmitting movements of said tracer stylus to said cutter spindle; powered mechanism for engaging and moving said tracer stylus in the direction the reverse of the direction of tracing movement thereof to an inactive position spaced radially from and out of tracing engagement with said profile surface upon completion of a tracing cycle and through said movement transmitting mechanism to simultaneously move said cutter spindle laterally to position for retraction thereof to non-working position; and interlock means for efiecting operation of said powered feed mechanism for said cutter spindle for retracting the latter from working to non-working position when said tracer stylus reaches said inactive position radially spaced from said profile surface. 7

6. In a profile milling machine, in combination, a supporting structure; a worktable; a cutter spindle mounted for universal lateral movements over said worktable; a master unit mounted on said supporting structure and having thereon a profile surface; a tracer stylus mounted for movements in either direction along said profile surface and being also mounted for movements bodily radially between tracing position in engagement with said profile surface and inactive position spaced radially therefrom; a powered drive for moving said tracer stylus in one direction along said profile surface through a tracing cycle, said powered drive including clutch means operable for engaging and disengaging said tracer stylus with and from driving connection with said powered drive; a pantograph linkage connected between said tracer stylus and said cutter spindle for transmitting movements of said tracer stylus to said cutter spindle; interlock means operable by said tracer stylus upon completion of a tracing cycle for efiiecting operation of said clutch means to disengage said tracer stylus from said powered drive; and means operative upon disconnection of said clutch means from said tracer stylus for moving said tracer stylus radially relative to said profile surface to inactive position spaced radially therefrom and through said pantograph linkage simultaneously moving said cutter spindle laterally.

7. In a profile milling machine, in combination a supporting structure; a worktable; a cutter spindle mounted for universal lateral movements over said worktable; a

master unit including a profile surface thereon, a tracer stylus mounted for movements in either direction along said profile surface and for movements bodily radially relative to said surface between aposition'in tracing engagement therewith and an inactive position spaced radially therefrom; powered drive mechanism for moving said tracer stylus in one direction along said profile surface through a tracing cycle; means operable to connect and disconnect said powered drive means to and from driving connection with said tracer stylus; a pantograph linkage connected between said tracer stylus and said cutter spindle for transmitting movements of said tracer stylus to said cutter spindle; interlock means operable by said tracer stylus when the latter completes its movement through a tracing cycle along said profile surface to operate said means to disconnect said powered drive means from said tracer stylus for movements freely of said tracer stylus in the direction the reverse of the direction of movement thereof through a tracing cycle; and independent powered means for moving said tracer stylus when disconnected from said powered drive means to inactive position spaced radially from said profile surface and simultaneously through said pantograph linkage to correspondingly move said cutter spindle laterally.

8. In a profile milling machine, in combination, a supporting structure; a worktable; a cutter spindle mounted for universal lateral movements over said worktable; a master unit having a profile surface thereon mounted on said supporting structure; a tracer stylus mounted for movements in either direction along said profile surface and being also mounted for movements radially relative to said profile surface; a powered drive mechanism for moving said tracer stylus in one direction along said profile surface through a tracing cycle; biasing mews acting to continuously yieldingly bias said tracer stylus radially into tracing engagement with said profile surface; a pantograph linkage coupled between and connecting said tracer stylus and said cutter spindle for transmitting movements of said tracer stylus to said cutter spindle; means operative to displace said tracer stylus radially to an inactive position spaced from said profile surface and through said pantograph linkage to simultaneously correspondingly laterally displace said cutter spindle; said cutter spindle being also mounted for movements axially between a working position and a non-working position relative to said worktable; powered feed means for retracting said cutter spindle from working position to nonworking position and for feeding said cutter spindle from non-working position to working position; and interlock means operatively controlled by said tracer stylus for effecting operation of said powered feed means for retracting said cutter spindle from working to non-working position when said tracer stylus is moved to inactive position.

9. In a profile milling machine, in combination, a sup porting structure; a cutter spindle mounted for universal lateral movements over said worktable; a profile surface supported in normally fixed position from said supporting structure; a tracer stylus mounted for movements in either direction along said profile surface and being also mounted for movements bodily radially relative to said profile surface between a tracing position in engagement therewith and an inactive position spaced radially therefrom; means for moving said tracer stylus in one direction along said profile surface in tracing engagement therewith through a tracing cycle; a pantograph linkage connected between said tracer stylus and said cutter spindle for transmitting movements of said tracer stylus to said cutter spindle as corresponding lateral movements of the latter; and means operable by said tracer stylus upon the completion of movement through a tracing cycle for moving said tracer stylus to said inactive position and simultaneously through said pantograph linkage moving said cutter spindle laterally to a corresponding laterally displaced position.

10. In a profile milling machine, in combination, a supporting structure; a worktable; a cutter spindle mounted for universal lateral movements over said worktable; a profile surface supported from said supporting structure in a normally fixed position; a tracer stylus mounted for movements in either direction along said profile surface and being also mounted for movements bodily radially relative to said profile surface between a tracing position in engagement therewith and an inactive position spaced radially therefrom; a pantograph linkage connected between said tracer stylus and said cutter spindle for transmitting movements of said tracer stylus to said cutter spindle as corresponding movements laterally of the latter; a powered drive mechanism for moving said tracer stylus in one direction along said profile surface in tracing engagement therewith through a tracing cycle; means for connecting said powered drive mechanism with and disconnecting said powered drive mechanism from said tracer stylus; powered means for moving said tracer stylus in the direction opposite the direction of movement thereof through a tracing cycle when said powered drive mechanism is disconnected from said tracer stylus; and guide means engageable by said tracer stylus when moved in said opposite direction for displacing said tracer stylus radially to said inactive position.

11. In a profile milling machine, in combination, a supporting structure; a worktable; a cutter spindle mounted for universal lateral movements over said worktable; a profile surface supported in normally fixed position from said supporting structure; a tracer stylus mounted for movements in either direction along'said profile surface and being also mounted for movements bodily radially relative to said profile surface between a tracing position in engagement therewith and an inactive position spaced radially therefrom; a powered drive mechanism for moving said tracer stylus in one direction along said profile surface in tracing engagement therewith through a tracing cycle; a powered means for moving said tracer stylus in the direction opposite the direction of movement thereof through a tracing cycle to said inactive position spaced radially from said profile surface; a pantograph linkage connected between said tracer stylus and said cutter spindle for transmitting movements of said tracer stylus to said cutter spindle as corresponding lateral movements of the latter; and interlock means operable by said tracer stylus when the latter completes its movement through a tracing cycle for effecting operation of said powered means to move said tracer stylus to its said inactive position spaced radially from said profile surface and through said pantograph linkage to simultaneously correspondingly laterally displace said cutter spindle.

12. In a profile milling machine, in combination, a supporting structure; a worktable; a cutter spindle mounted for universal lateral movements over said worktable and being also mounted for feeding movements axially thereof between a working position and a non-working position relative to said worktable; powered feed means for feeding said cutter spindle between working and nonworking positions; a profile surface supported in normally fixed position from said supporting structure; a tracer stylus mounted for movements in either direction along said profile surface and being also mounted for movements radially relative to said profile surface between a tracing position in engagement therewith and an inactive position spaced radially therefrom; a powered drive mechanism for moving said tracer stylus in one direction along said profile surface through a tracing cycle; a pantograph linkage connected between said tracer stylus and said cutter spindle for transmitting movements of said tracer stylus to said cutter spindle; powered means for moving said tracer stylus laterally from tracing position in engagement with said profile surface to said inactive position spaced laterally therefrom; interlock means operable by said tracer stylus when the latter completes its movement through a tracing cycle to effect op- 

